U.S. patent number 7,789,105 [Application Number 11/753,274] was granted by the patent office on 2010-09-07 for gas pressure regulator.
This patent grant is currently assigned to O.M.T. Officina Meccanica Tartarini S.r.I.. Invention is credited to Andrea Monti, Stefano Zecchi.
United States Patent |
7,789,105 |
Zecchi , et al. |
September 7, 2010 |
**Please see images for:
( Certificate of Correction ) ** |
Gas pressure regulator
Abstract
The gas pressure regulator (1) comprises a main body (2) having
a first, gas inlet pipe (4) and a second, gas outlet pipe (6), a
calibrated gas passage (8) through which the gas flows from the
first pipe (4) to the second pipe (6), a shutter (9) housed at
least partially in the main body (2) and a silencing element (102)
also housed in the body (2).
Inventors: |
Zecchi; Stefano (Bologna,
IT), Monti; Andrea (Funo de Argelatio,
IT) |
Assignee: |
O.M.T. Officina Meccanica Tartarini
S.r.I. (Castel Maggiore (Bologna), IT)
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Family
ID: |
38521348 |
Appl.
No.: |
11/753,274 |
Filed: |
May 24, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070272316 A1 |
Nov 29, 2007 |
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Foreign Application Priority Data
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Mar 10, 2007 [IT] |
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BO 2006 A 000400 |
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Current U.S.
Class: |
137/625.33;
251/127; 137/625.39 |
Current CPC
Class: |
F16K
47/08 (20130101); G05D 16/0658 (20130101); F16K
1/427 (20130101); Y10T 137/86759 (20150401); Y10T
137/86807 (20150401) |
Current International
Class: |
F16K
47/02 (20060101) |
Field of
Search: |
;137/625.33,625.34,625.35,625.36,625.37,625.38,625.39,42,44
;251/127 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 167 252 |
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Jan 1986 |
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EP |
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2 277 792 |
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Nov 1994 |
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GB |
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WO 2006/100603 |
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Sep 2006 |
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WO |
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Other References
International Search Report for International Application No.
PCT/IB2007/001354, dated Oct. 16, 2007. cited by other .
Written Opinion for International Application No.
PCT/IB2007/001354, dated Oct. 16, 2007. cited by other.
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Primary Examiner: Fox; John
Attorney, Agent or Firm: Marshall, Gerstein & Borun
LLP
Claims
What is claimed is:
1. A gas pressure regulator comprising: a main body having a first,
gas inlet pipe and a second, gas outlet pipe; a calibrated gas
passage through which the gas flows from the first pipe to the
second pipe; a shutter housed at least partially in the main body
and mobile to adjust the opening of calibrated passage between an
end position in which the passage is fully open and an end position
in which the passage is closed; the shutter, when at the closed end
position, engaging with a locating groove; a silencing element
located at the calibrated passage to reduce the noise produced
inside the pressure regulator, the silencing element comprising a
substantially cylindrical wall having a plurality of openings
through which the gas passes; and at the gas passage, an axially
symmetric body for housing the silencing element, the axially
symmetric body comprising a peripheral wall with a plurality of
windows through which the gas passes, and the locating groove being
integral with the axially symmetric body.
2. The pressure regulator according to claim 1, wherein the axially
symmetric body comprises an annular portion extending from the
peripheral wall towards the inside of the body itself, the annular
portion forming the locating groove.
3. The pressure regulator according to claim 2, wherein the annular
portion comprises an annular cavity which accommodates the lower
edge of the cylindrical wall of the silencing element.
4. The pressure regulator according to claim 1, wherein the
silencing element is removably housed in the peripheral wall of the
axially symmetric body.
5. The regulator according to claim 4, wherein the silencing
element has a break in its circumference designed to enable the
silencing element to be elastically deformed so as to reduce its
circumferential dimension.
6. The regulator according to claim 5, wherein the silencing
element, when elastically deformed, is inserted into the peripheral
wall of the axially symmetric body.
7. The pressure regulator according to claim 6, wherein the
silencing element exerts an elastic force in a substantially radial
direction against the peripheral wall of the axially symmetric
body.
8. The regulator according to claim 1, wherein the silencing
element is made from sheet metal and the openings for the passage
of the gas are circular holes.
9. The regulator according to claim 1, wherein the silencing
element is made from rigid wire mesh.
10. The regulator according to claim 1, wherein the silencing
element is made of ceramic material.
11. The regulator according to claim 1, wherein the silencing
element is made of plastic.
12. The regulator according to claim 1, where the shutter is
slidably housed in a cylindrical liner stably fixed to the main
body, wherein the axially symmetric body is positioned between the
liner and a portion of the main body in such a way that the gas
flowing from the calibrated passage is forced to follow a
well-defined path.
Description
RELATED APPLICATIONS
This application claims priority to Italian application number
BO2006 A0004000 dated May 24, 2006.
TECHNICAL FIELD
This invention relates to a gas pressure regulator.
In particular, the invention relates to a pressure regulator fitted
with a noise reducing device.
Pressure regulators currently used are also commonly known as
"pressure reducers" because their regulating action is achieved by
reducing the gas delivery pressure through laminar flow
elements.
Regulators known in prior art basically comprise a main body with
an inlet through which gas flows in at high pressure and an outlet
through which the gas flows out at reduced pressure. This main body
houses means for controlling and regulating the gas flow.
The controlling and regulating means comprise at least one shutter,
actuated by spring and diaphragm systems which enable the shutter
to slide on its shaft, and a pilot device which measures the
pressure of the gas upstream and downstream of the regulator and
diaphragm accordingly.
The shutter, usually cylindrical in shape, can move axially between
two limit positions: a first gas shutoff position where it is
substantially in contact with a respective housing and a second
fully open position corresponding to the maximum size of the gas
flow port.
The gas flow is shut off by means of a ring seal or pad, normally
fixed to the mobile shutter and adapted to engage the housing. The
gas laminar flow effect is therefore concentrated at the
housing.
This creates a great deal of noise when the reducer is operating
under steady-state conditions.
The noise is caused by the physical processes that occur during
pressure reduction: the gas flows out of the choked section defined
by the diaphragm at a high speed which, under "hypercritical"
pressure drop conditions, may even reach the speed of sound; thus,
the speed of the gas flowing out of the choked section differs
considerably from the speed of the gas in the pipe downstream, this
difference creating gas bubbles of varying size (known in the
jargon of the trade as "turbulence bubbles") which are expelled
continuously by the gas flow itself. The pressure oscillations
caused by this process produce noise. The higher the flow speed is,
the more the noise. The noise caused by this effect is transmitted
to the pipe downstream which in turn becomes a source of noise.
Furthermore, during the "hypercritical" pressure drop, the change
from inflow pressure to outflow pressure occurs in non-stationary
stages (called "shock waves") which cause rising surges of noise.
These waves also cause mechanical vibrations which produce yet more
noise.
In recent years, manufacturers of pressure regulators have
concentrated their research on silencing devices with a view to
reducing regulator noise emissions.
To date, two types of silencing devices are used: silencers that
act on the source of the noise and those that reduce the noise
actually generated.
Those of the former type include both flow dividing devices and
devices that separate the total pressure stage into a plurality of
lower pressure stages.
Those of the latter type, which reduce the noise generated, act by
absorption and are located downstream of the gas lamination area.
These devices usually comprise cartridges made of porous material
designed to absorb the sound waves.
Of all the above mentioned devices, the sound absorption devices
are the most complex and cumbersome since the cartridges have to be
placed inside the pressure regulator bodies. The regulator body
therefore has to be larger to accommodate the cartridge which in
turn means heavier regulators and higher costs.
The devices that operate by separating the pressure stage are also
very complex, even at the design stage, involving considerable
complications in the very structure of the regulator.
Of the above mentioned devices, flow dividers are without doubt the
most practical and economical since they basically comprise a
surface through which the gas passes and which breaks the gas flow
up into a plurality of smaller flows, which, as demonstrated in
numerous experiments, considerably reduces the amount of noise
produced. These devices, however, are not entirely free of
disadvantages.
The main disadvantage is that they cannot be installed unless the
pressure regulator is totally disassembled. That means that once a
certain type of silencing device has been installed, it cannot be
substituted without completely disassembling the regulator. In many
cases, however, the silencing device in a regulator that has
already been installed has to be replaced because it exceeds
permitted noise levels or because it has to be adapted to different
flow conditions.
The silencing device may also need to be substituted when worn.
In these situations, changing the silencing devices in prior art
pressure regulators involves considerable assembly
difficulties.
SUMMARY OF THE INVENTION
The aim of this invention is to provide a pressure regulator that
overcomes the above mentioned disadvantages and that is simple and
inexpensive to assemble and practical to maintain.
The technical characteristics of the invention according to the
aforementioned aims may be easily inferred from the contents of the
appended claims, especially claim 1, and also any of the claims
that depend, either directly or indirectly, on claim 1.
BRIEF DESCRIPTION OF THE DRAWINGS
Moreover, the advantages of the invention are apparent from the
detailed description which follows, with reference to the
accompanying drawings which illustrate a preferred embodiment of
the invention provided merely by way of example without restricting
the scope of the inventive concept, and in which:
FIG. 1 illustrates a preferred embodiment of the pressure regulator
according to the invention in a schematic cross section;
FIG. 2 is a perspective view from above of two disassembled parts
of the pressure regulator of FIG. 1;
FIG. 3 is a perspective view from above of the two parts of FIG. 2
before being assembled;
FIG. 4 is a perspective view from above of the two parts of FIG. 2
after being assembled;
FIG. 5 is a schematic view in cross section, of the pressure
regulator of FIG. 1 during the assembly/disassembly steps shown in
FIGS. 2 to 4;
FIG. 6 is a schematic side elevation section view of another
embodiment of the parts shown in FIG. 2;
FIG. 7 is a schematic section view of the two parts of FIG. 6 after
being assembled.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, the numeral 1 denotes in its entirety a
gas pressure regulator made in accordance with this invention.
The pressure regulator 1 comprises a main body 2 with an inlet
opening 3 through which the gas enters at a first delivery
pressure, said inlet opening 3 being connected to a respective
first inlet pipe 4, and a gas outlet opening 5 connected to a
respective second outlet pipe 6 in which the gas flows at a
pressure that is different from the delivery pressure.
The second outlet pipe 6 is located downstream of the first inlet
pipe 4 relative to the direction, indicated by the arrow F1, in
which the gas flows through the regulator 1.
Between the first pipe 4 and the second pipe 6 there is an axially
symmetric body 7, which will be described in detail below, said
body 7 defining a calibrated gas passage 8.
The regulator 1 also comprises, inside it, a shutter 9 that moves
lengthways along a first defined line D to adjust the opening of
the calibrated passage 8 between a first end position, illustrated
in FIG. 1, in which the passage is closed, and a fully open
position which is not illustrated in the accompanying drawings.
The shutter 9 comprises a hollow cylindrical body 10 having a
central axis A and, at its lower end 9a, an element 11 for shutting
off the calibrated passage 8.
The shut-off element 11 comprises two blocks 11a, 11b attached to
the cylindrical body 10, the two blocks 11a, 11b having, tightened
between them, a seal pad 12 designed to engage a respective
locating groove 101 in order to close the gas passage 8. As shown
in 2, the groove 101 is ring-shaped and is formed integrally in the
axially symmetric body 7.
The calibrated gas passage 8 is shown in FIG. 1 in a substantially
closed condition and, in use, is defined by the gap created between
the seal pad 12 and the respective locating groove 101 when the
shutter 9 moves.
With reference to FIG. 1, the main body 2 has fitted over it a
device 14 for actuating the shutter 9, the device 14 comprising a
first, upper concave cover 15 and a second, lower, concave cover
16, coupled in such a way that their concavities face each other to
delimit a volume V.
The volume V houses an annular diaphragm 17 whose outer edge is
held tight between the two covers 15, 16, the diaphragm 17 dividing
the volume V into two chambers V1, V2 whose volumetric size varies
as a function of the operating parameters of the pressure regulator
1.
The actuating device 14 also comprises two flanges 18 and 19,
respectively upper and lower, which hold tight between them an
inside edge of the annular diaphragm 17.
The regulator 1 also comprises a cylindrical liner 13 that slidably
houses the shutter 9, the liner 13 being stably attached to the
lower concave cover 16.
Looking in more detail, as clearly shown in FIG. 5, the lower cover
16 has a central circular opening 200 whose inside surface has a
threaded portion 201.
Similarly, a portion 13a of the outside surface of the cylindrical
liner 13 is threaded so that it can be screwed to the threaded
portion 201 of the cover 16.
Thus, the liner 13 can be inserted into, and extracted from, the
main body 2 without having to remove the lower cover 16 from its
housing.
The two flanges 18, 19 are securely joined to each other and
connected to the shutter 9 by a plurality of fastening elements
21.
The cylindrical body 10 of the shutter 9 houses a regulator spring
unit 30 comprising a helical spring 31 acting by compression along
is axis A, and a first and a second regulator plate 33, 34,
respectively upper and lower, positioned in contact with respective
opposite ends of the spring 31.
The lower regulator plate 34 abuts against a circumferential ledge
made inside the hollow cylindrical body 10.
A ring nut 45 is screwed to a respective threaded inside portion at
the top end 9b of the shutter 9.
The regulator 1 also comprises a silencing element 102 of the flow
dividing type housed in the axially symmetric body 7.
As clearly shown in FIGS. 2 to 4, the silencing element 102
comprises a substantially cylindrical wall 103 with a plurality of
holes 104 made in it to form the openings through which the gas
passes. For simplicity, only some of the holes 104 are shown in the
accompanying drawings.
In another embodiment, illustrated in FIGS. 6 and 7, the silencing
element 102 comprises a cylindrical wall 110 made from wire
mesh.
The cylindrical wall 110 comprises two opposite circumferential
edges 112 where respective stiffening rings 113 are fitted to
enable the axially symmetric body 7 to be mounted.
With reference to FIG. 2, which illustrates the element 102 and the
body 7 removed from the regulator 1, the axially symmetric body 7
comprises a cylindrical peripheral wall 70 with a plurality of
windows 71, which are approximately quadrangular in shape and
equally spaced around the circumference of the wall 70 itself.
Each of the windows 71 forms a respective port through which the
gas passes from the first pipe 4 to the second pipe 6 of the
regulator 1.
As stated above, FIG. 2 clearly illustrates the silencing element
102 removed from the axially symmetric body 7; the element 102 is
made, preferably but not necessarily, from sheet metal with the
holes 104 made in it.
The effect of the holes 104 is to divide the gas flow passing
between the first pipe 4 and the second pipe 6 into a plurality of
smaller flows, at least for a short distance in the proximity of
the gas pressure regulation area. As a result of this division,
based on substantially known fluid dynamic events which will not be
described since they fall outside the scope of the invention, the
amount of noise generated is considerably reduced. This reduction
has been demonstrated experimentally.
The axially symmetric body 7 also comprises an annular portion 72
starting at a bottom area 70a of the cylindrical wall 70 and
extending towards the inside of the body 7 itself.
As illustrated in FIGS. 1 and 2, the annular portion 72 forms the
above mentioned locating groove 101 of the shutter 9.
The annular portion 72 of the body 7 further comprises a cavity 73,
also annular.
As clearly illustrated in the accompanying drawings and described
in more detail below, the silencing element 102 is removably housed
in the axially symmetric body 7.
Looking in more detail, with reference to FIGS. 2 to 4, the above
mentioned annular cavity 73 formed in the portion 72 accommodates,
in the assembled configuration, a bottom edge 103a of the
cylindrical wall 103 of the silencing element 102.
As illustrated in FIG. 2 the silencing element 102 has a break in
its circumference, that is to say, a gap in the cylindrical wall
103, said break being designed to enable element 102 to be
elastically deformed. FIG. 3 shows how the elastic deformation
reduces the circumferential dimension of the silencing element
102.
The circumferential break is preferably, but not necessarily, made
in the sheet metal element 102.
If the silencing element 102 comprises a wall 110 made from wire
mesh, it does not have the circumferential break in it.
In other possible embodiments of the silencing element 102 that are
not illustrated, the cylindrical wall 103 is made of plastic or
ceramic material instead of metal.
In other words, the lateral surface of the cylindrical wall 103
that defines the silencing element 102 is not continuous and
therefore has two facing end edges 103b, 103c which are spaced
apart when removed from the axially symmetric body 7.
The elasticity of the material the wall 103 is made of enables the
two spaced edges 103b, 103c to be moved closer together with a
minimal effort by elastically deforming the cylindrical wall 103
itself. Moving the edges 103b, 103c closer together reduces the
overall circumferential dimension of the silencing element 102 so
that it can be inserted into the axially symmetric body 7, as
clearly illustrated in FIGS. 3 and 4.
Once inside the axially symmetric body 7 in an elastically deformed
configuration, the silencing element 102 exerts a corresponding
elastic force in a substantially radial direction against an inside
face 70b of the cylindrical wall 70 of the axially symmetric body
7.
As shown in FIG. 1, the axially symmetric body 7 is positioned
between the liner 13 and a portion of the main body 2 in such a way
that the gas flowing from the inlet pipe 4 to the calibrated
passage 8 is forced to follow a well-defined path.
The above mentioned elastic force holds the silencing element 102
and the axially symmetric body 7 firmly together, preventing them
from sliding relative to each other even if the gas flows through
the regulator 1 under high pressure.
If the silencing element 102 comprises a wall 110 made from wire
mesh, it is advantageously inserted into the axially symmetric body
7 in such a way that the stiffening rings 113 are pressed against
the inside face 70b of the body 7 thus firmly holding the body 7 in
place during operation but allowing it to be easily removed for
maintenance purposes and/or to change it.
FIGS. 1 and 5 show how the axially symmetric body 7 is positioned
in a stepped circumferential housing 202 formed in the main body of
2 of the regulator 1 and, when the regulator 1 is assembled, is
held in place by the liner 13. At the lower end 13b of the liner
13, there is a respective step 203 designed to engage with the
upper edge 70c of the axially symmetric body 7.
As illustrated in FIG. 5, the axially symmetric body 7 and/or the
silencing element 102 can be fitted to, and/or extracted from, the
pressure regulator 1 by simply removing certain parts of the
regulator 1 itself without, for example, having to removing the
bottom cover 16.
Also, thanks to the axially symmetric body 7, different types of
silencers, such as, for example, perforated metal sheet or wire
mesh, can be used interchangeably, and can be easily removed and
fitted.
* * * * *